# Confidence intervals

• Feb 7th 2010, 02:29 AM
SirOJ
Confidence intervals
i've just started a statistics module this semester and am lagging behind a bt due to work commitments. See Example question below

Sample Size = 74
Sample Mean = 3.98
Sample Standard Deviation = 4.4

Construct a 99% confidence interval...

If someone could point me in the right direction of solving this (probably easy) problem it would help me greatly
• Feb 7th 2010, 02:33 AM
mr fantastic
Quote:

Originally Posted by SirOJ
i've just started a statistics module this semester and am lagging behind a bt due to work commitments. See Example question below

Sample Size = 74
Sample Mean = 3.98
Sample Standard Deviation = 4.4

Construct a 99% confidence interval...

If someone could point me in the right direction of solving this (probably easy) problem it would help me greatly

The right direction points to your textbook or class notes where you will find the necessary formula and, no doubt, several examples (see Student's t-distribution). You will also find many threads in this subforum that are relevant to your question..
• Feb 7th 2010, 07:23 AM
matheagle
Quote:

Originally Posted by SirOJ
Construct a 99% confidence interval...

For what?
We're guessing you want a CI for the population mean, or maybe the standard deviation?
Do you have normality here?
• Feb 7th 2010, 08:26 AM
SirOJ
yes, for the population mean. I think i have it figured out now after searching through the archives on this forum